US5104426A - Method of and apparatus for separating gas mixture - Google Patents
Method of and apparatus for separating gas mixture Download PDFInfo
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- US5104426A US5104426A US07/608,350 US60835090A US5104426A US 5104426 A US5104426 A US 5104426A US 60835090 A US60835090 A US 60835090A US 5104426 A US5104426 A US 5104426A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
- B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
- B01D53/0407—Constructional details of adsorbing systems
- B01D53/0446—Means for feeding or distributing gases
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
- B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
- B01D53/047—Pressure swing adsorption
- B01D53/0476—Vacuum pressure swing adsorption
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2256/00—Main component in the product gas stream after treatment
- B01D2256/12—Oxygen
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/10—Single element gases other than halogens
- B01D2257/102—Nitrogen
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2259/00—Type of treatment
- B01D2259/40—Further details for adsorption processes and devices
- B01D2259/40007—Controlling pressure or temperature swing adsorption
- B01D2259/40009—Controlling pressure or temperature swing adsorption using sensors or gas analysers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2259/00—Type of treatment
- B01D2259/40—Further details for adsorption processes and devices
- B01D2259/40011—Methods relating to the process cycle in pressure or temperature swing adsorption
- B01D2259/40013—Pressurization
- B01D2259/40016—Pressurization with three sub-steps
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2259/00—Type of treatment
- B01D2259/40—Further details for adsorption processes and devices
- B01D2259/40011—Methods relating to the process cycle in pressure or temperature swing adsorption
- B01D2259/40028—Depressurization
- B01D2259/4003—Depressurization with two sub-steps
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2259/00—Type of treatment
- B01D2259/40—Further details for adsorption processes and devices
- B01D2259/40011—Methods relating to the process cycle in pressure or temperature swing adsorption
- B01D2259/40035—Equalization
- B01D2259/40037—Equalization with two sub-steps
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2259/00—Type of treatment
- B01D2259/40—Further details for adsorption processes and devices
- B01D2259/40011—Methods relating to the process cycle in pressure or temperature swing adsorption
- B01D2259/40043—Purging
- B01D2259/4005—Nature of purge gas
- B01D2259/40052—Recycled product or process gas
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2259/00—Type of treatment
- B01D2259/40—Further details for adsorption processes and devices
- B01D2259/40011—Methods relating to the process cycle in pressure or temperature swing adsorption
- B01D2259/40058—Number of sequence steps, including sub-steps, per cycle
- B01D2259/40067—Seven
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2259/00—Type of treatment
- B01D2259/40—Further details for adsorption processes and devices
- B01D2259/40011—Methods relating to the process cycle in pressure or temperature swing adsorption
- B01D2259/40077—Direction of flow
- B01D2259/40081—Counter-current
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2259/00—Type of treatment
- B01D2259/40—Further details for adsorption processes and devices
- B01D2259/402—Further details for adsorption processes and devices using two beds
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/02—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
- B01D53/04—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography with stationary adsorbents
- B01D53/047—Pressure swing adsorption
- B01D53/0473—Rapid pressure swing adsorption
Definitions
- This invention relates to a method of separating gas mixture by pressure swing adsorption and an apparatus executing the method and more particularly to technologies suitable for separating oxygen from air and for enriching oxygen efficiently.
- pressure swing adsorption methods for separating oxygen and nitrogen from air have been used by repeating adsorption and desorption in turn with assistance of pressure changes.
- Such methods comprise an adsorption process for producing oxygen as product by allowing nitrogen to be selectively adsorbed after feeding air pressurized by a compressor to an adsorber packed with a solid adsorbent such as synthetic zeolite, for example, 5A.3X; a regeneration process for desorbing nitrogen in the adsorbent by depressurizing the adsorber after completion of the adsorption process; and a pressurization process for pressurizing the adsorber with product oxygen or air up to the pressure for adsorption process after completion of the regeneration process.
- a column in which the adsorption process is occurring is fed continuously with feedstock air so as to continue producing oxygen until immediately before nitrogen adsorption zone reaches the product outlet end of adsorption bed.
- the adsorbent which can still adsorb more nitrogen, i.e., there exists oxygen which can still be produced as product by further adsorption of nitrogen from feedstock air.
- the remaining oxygen is discharged outside the system without being taken out as product at the stage of shifting from the adsorption process to the succeeding regeneration process by means of vacuum pump etc., thus reducing the above-mentioned recovery rate of product oxygen.
- a single column system is employed to achieve improvement in recovery rate of product oxygen by depressurizing the adsorber, to discharge product oxygen at reduced pressure, in accordance with adsorption pressure conditions so as to allow longitudinal width of the nitrogen adsorption zone to be reduced for the purpose of reducing remaining oxygen quantity in the nitrogen adsorption zone at the outlet end of packed bed which is discharging product oxygen, before the nitrogen adsorption zone reaches the outlet end.
- step 1a while column 200A is under adsorption process, column 200B, which has already completed the adsorption process, is in the course of regeneration process. Secondly, at the stage of shifting from step 1a to step 1b, supply of feedstock air into column 200A is ceased, and regeneration process in column 200B is completed. At step 1b, oxygen which is highly enriched in column 200A is supplied into column 200B via nozzle part. The supply is continued until the pressure in column 200A becomes equal to or slightly higher than that in column 200B.
- the nozzle at the top of the column 200A is connected to the nozzle at the bottom of column 200B, and the enriched oxygen remaining in the vicinity of the top of column 200A is transferred into column 200B via the nozzle at the bottom thereof.
- the high-enriched oxygen supplied from the nozzle at the top of column 200A at step 1B is eventually discharged from the nozzle at the top of column 200B by the gas transfer.
- nitrogen with high concentration is fed through the nozzle at the bottom of column 200A. With this high-concentrated nitrogen, oxygen remaining in column 200A is purged out and transferred into column 200B.
- column 200A is subjected to regeneration process and column 200B which is fed with feedstock air is subjected to adsorption process.
- This method aims at improving the recovery rate of product oxygen by purging out the oxygen remaining in column 200A with high-concentrated nitrogen to recover the oxygen.
- this technology poses a problem in that oxygen recoverable as product remains more or less in the vicinity of the outlet end of the adsorption bed, and no attention is paid to the reduction in the effect on improving the recovery rate of product oxygen, and also to the reduction in the quantity of the oxygen which can be produced per unit volume of the adsorbent due to the presence of the adsorbent which does not contribute to the separation of feedstock air.
- column 300A is shifted to the regeneration step, while column 300B is subjected to pressurization step using product oxygen.
- pressurization step it is required to cease the adsorption step when column 300A is in the adsorption step under a condition that a considerable amount of high-enriched oxygen remains in the adsorbent. (There is a case that more than half of the adsorbent bed is filled with the high-enriched-oxygen.) This is because as soon as high-enriched-oxygen is transferred into column 300B and the latter is subjected to the adsorption step, the high-enriched oxygen needs to be discharged.
- the adsorption step of column 300A needs to be completed under a condition that the high-enriched-oxygen is held in the vicinity of the outlet end of the adsorption bed. Therefore, the pressure swing adsorption process including the pressure equalization step poses a problem in that no consideration is taken on lowering of effect on improving the recovery rate of product oxygen due to oxygen recoverable as product oxygen remaining more or less in the outlet end of the adsorption bed.
- the nitrogen adsorption zone can proceed only up to the medium height of the column 300A. In such a state, a great deal of adsorbent which can adsorb more nitrogen remains in the adsorbent bed, so that adsorbent can not be utilized efficiently. Therefore, there is another problem in that no consideration is taken on the reduction in the quantity of oxygen which can be produced per unit volume of adsorbent.
- suspension of feedstock air supply causes a reduction in the quantity of feedstock air to be treated per unit volume of the adsorbent, if the same operational time is allocated for each of the above-mentioned processing, and that reduction in the quantity of oxygen which can be produced as product take places.
- the adsorbent is expensive, increase in plant costs such as the cost of adsorbent at the time of plant construction and also the cost of adsorbent for replenishment during ordinary operation is inevitable.
- the present invention has for its object to increase the quantity of product oxygen per unit volume of an adsorbent in the pressure swing adsorption process with two-column system, thereby achieving considerable reduction in the construction cost of oxygen production facilities.
- the present invention aims at lowering the construction cost of coal gasification complex power generation plant.
- a gas mixture separating apparatus comprising: an adsorption column packed with an adsorbent; a gas mixture column-end feeding device for feeding a gas mixture to one of two ends of the adsorption column; an unadsorbed-gas column-end discharging device for discharging unadsorbed gas from the other end of the adsorption column; a pressurizing device for pressurizing the gas mixture to be fed to the end of the adsorption column: and an adsorber depressurizing device connected to the end of the adsorption column on the gas mixture feed side; characterized in that it further comprises a gas mixture side-injection device for feeding said gas mixture to the adsorbent in the adsorption column from the shell side thereof.
- a gas mixture separating apparatus comprising: an adsorption column packed with an adsorbent; a gas mixture column-end feeding device for feeding a gas mixture to one of two ends of the adsorption column: an unadsorbed-gas column-end discharging device for discharging unadsorbed gas from the other end of the adsorption column; an unadsorbed-gas column-end feeding device for adsorbent regeneration, which is connected to the side of the adsorption column where the unadsorbed gas is discharged; a gas mixture pressurizing device for pressurizing the gas mixture; and an adsorber depressurizing device connected to the end of the adsorption column on the gas mixture feed side, characterized in that it further comprises a gas mixture side-injection device for feeding said gas mixture to the adsorbent in the adsorption column from shell side thereof, and an unadsorbed-gas side-injection device for feeding the
- a gas mixture separating apparatus comprising: an adsorption column packed with an adsorbent; a gas mixture feeding device for feeding a gas mixture to one of two ends of the adsorption column; an unadsorbed-gas discharging device for discharging an unadsorbed gas from the other end of the adsorption column; a first unadsorbed-gas column-end feeding device connected to the adsorption-column end on the unadsorbed gas discharge side; a gas mixture pressurizing device for pressurizing the gas mixture: an adsorber depressurizing device connected to the end of the adsorption column on the gas mixture feeding side and; a second unadsorbed gas column-end feeding device for feeding the unadsorbed gas from the end of the adsorption column on the gas mixture feed side, characterized in that it further comprises at least one of either gas mixture side-injection device for feeding the gas mixture to the ad
- a gas mixture separating apparatus comprising: an adsorption column packed with an adsorbent; a gas mixture column-end feeding device for feeding a gas mixture to one of two ends of the adsorption column: an unadsorbed gas column-end discharging device for discharging unadsorbed gas from the other end of the adsorption column; a gas mixture pressurizing device for pressurizing said gas mixture to be fed to the end of the adsorption column; and an adsorber depressurizing device connected to the end of the adsorption column, characterized in that it further comprises: a plurality of said gas mixture side-injection devices for feeding said gas mixture to the adsorbent in the adsorption column; a switching over device for switching over a plurality of said gas mixture side-injection devices one another; concentration sensors for detecting the concentration of the same sorts of components in gas flow as are adsorbed by the adsorbent in the adsorption column
- adsorption process in which a gas mixture is fed from one of two ends of an adsorption column packed with an adsorbent so as to allow adsorbable components in the gas mixture to be adsorbed and unadsorbed gas is discharged from the other end of the adsorption column: an adsorbent regeneration process wherein after completion of the adsorption process adsorbed components are desorbed by depressurizing the adsorption column by sucking gas therein in the opposite direction to the direction of gas mixture feeding; a pressurizing process wherein after the adsorbent regeneration process, the adsorption column is pressurized up to adsorption pressure either by refeeding the gas mixture into the adsorption column from the same direction as the gas mixture is fed or by feeding unadsorbed gas into the adsorption column; the adsorption process being repeated again after completion of the said pressuring process,
- the above-mentioned objects can be achieved by carrying out a method of separating gas mixture comprising: an adsorption process in which a gas mixture is fed from one of two ends of an adsorption column packed with an adsorbent so as to allow adsorbable components in the gas mixture to be adsorbed, and unadsorbed gas is discharged from the other end of the adsorption column; an adsorbent regeneration process wherein after completion of the adsorption process the adsorption column is depressurized by sucking gas in the adsorption column in the opposite direction to the feeding direction of the gas mixture and further the adsorbed components are purged by feeding the unadsorbed gas from the opposite direction; and a pressurizing process wherein after completion of the adsorbent regeneration process the adsorption column is pressurized to the adsorption pressure either by refeeding the gas mixture to the adsorption column from the same direction as the gas mixture is fed or by feeding the unadsorbed
- FIG. 1a is a diagram showing the configuration of an embodiment according to the present invention.
- FIG. 1b is a sectional view of a gas injection nozzle as shown in FIG. 1a;
- FIG. 1c is a diagram of a control system for switching over the gas injection nozzle of the column in the course of the adsorption process as shown in FIG. 1a:
- FIG. 1d is a diagram of a control system for switching over the column in the course of the product oxygen injection step as shown in FIG. 1a:
- FIG. 2 is a timing chart showing the operational schedule of the apparatus as shown in FIG. 1a:
- FIG. 3 is a block diagram showing gas flow patterns according to the operational schedules of the apparatus as shown in FIG. 2;
- FIG. 4 is a graph showing the relationship between the pressure and the quantity of nitrogen to be adsorbed during the adsorption process in the embodiment:
- FIG. 5 is a graph showing the relationship between the pressure and the quantity of nitrogen to be adsorbed during the regeneration process in the same embodiment:
- FIG. 6 is a block diagram showing gas flow patterns according to the operational schedules of the prior art
- FIGS. 7a and 7b are block diagrams showing the adsorptional condition in the adsorption column at each step of the prior art
- FIG. 8 is a diagram showing the configuration of a system on one side of the columns according to other embodiments of the present invention.
- FIG. 9 is a diagram showing the configuration of another system on the other side of the columns according to other embodiments of the present invention.
- Air as mixed gas feedstock is pressurized by compressor 2 through piping 50 up to a predetermined adsorption pressure P 1 , and is fed through pressure regulator valve 5A into column 1 selected by valve 11 as an adsorption column.
- Oxygen separated and enriched in column 1 which has been selected by valve 12 as an adsorber, is temporarily stored in product tank 4, and a great part of the oxygen stored in product tank 4 is withdrawn to outside of the system concerned through the line 90, and a part of it is transferred and injected into column 1 selected by valve 14 through pressure regulator valve 5B so as to pressurize column 1 and to keep the pressure in column 1 constant.
- Desorbed gas during adsorbent regeneration is sucked by vacuum pump 2 from column 1 selected by valve 13 and vented into atmosphere through piping 60.
- column 1A In the first half of one cycle, column 1A is in adsorption operation, whereas column 1B is in desorption operation, and vice versa in the second half.
- FIG. 2 illustrates chronological change in pressure in columns 1A and 1B in relation to operation time at each step of columns 1A and 1B.
- FIG. 3 Gas flow in the above-mentioned operation is shown in FIG. 3.
- air pressurized by compressor 2 up to P 1 of 1.2 ata is fed from nozzle 110A into column 1A through pressure regulator valve 5A and valve 11A, and initial adsorption step 1A-1 is executed during pressurization of column 1A from P 2 of 0.9 ata to P 1 of 1.2 ata.
- main adsorption step 1A-2 at pressure P 1 of 1.2 ata will follow.
- step 1A-2 enriched oxygen is fed from nozzle 100A through valve 12A and piping 70 into tank 4 and stored therein.
- column 1B is depressurized by vacuum pump 3 from P 1 of 0.9 ata to P d of 0.48 ata, and as a result, nitrogen contained in an adsorbent is desorbed.
- Regeneration step 1B-4 at which desorbed gas is vented off via nozzle 110B, valve 13B and piping 60, is effected.
- Product oxygen in product tank 4 is injected through nozzle 100B into column 1B after pressure regulator valve 5B and valve 14B are opened.
- Product oxygen is injected so as to keep regeneration pressure P d constant at about 0.48 ata.
- the injection of product oxygen is aiming at accelerating desorption of nitrogen captured in the adsorbent and regeneration of the adsorbent by making use of difference in partial pressure between nitrogen and oxygen.
- regeneration step 1B-5 at which more acceleration of the nitrogen desorption is achieved, is carried out by depressurizing by means of vacuum pump 3 and by injection of product oxygen.
- valves 14B Near halfway progression of regeneration step 1B-5 valves 14B are closed and valve 30B is opened, and product oxygen is injected through gas injection nozzle 6B.
- column 1A Upon completion of regeneration step 1B-5 at column 1B, column 1A is still in the course of adsorption step 1A-2, during which valve 12A is closed and valves 15B and 16A are opened.
- oxygen concentration indicator (not illustrated in FIG. 1) indicates approximately 50% of product oxygen concentration (hereinafter referred as "medium-enriched oxygen"), in consequence, medium-enriched-oxygen is introduced from nozzle 100A into column 1B.
- pressurization step 1B-6 in column 1B is brought into operation in which the pressure of column 1B is increased from P d of 0.48 ata to level of P 3 of 0.7 ata by introducing a part of product oxygen in product tank 4 into column 1B after valve 13B is closed and pressure regulator valve 5B and valves 14B and 30B are opened.
- column 1A is in the course of adsorption step 1A-2, during which valve 20A is kept open until the concentration of oxygen reaches the level of 23% (hereinafter referred as "low-enriched oxygen") at the outlet end of the adsorption bed.
- valve 11B is opened. By such operation, air flow via valve 11B and low-enriched oxygen from valve 100A via valves 16A and 15B will flow together and are injected from nozzle 110B into column 1B.
- pressurization/adsorption step 1B-7 is effected, which includes pressurization step wherein the pressure in column 1B is increased from the level of pressure P 3 of 0.7 ata to that of pressure P 2 of 0.9 ata, and adsorption process by air introduction is proceeded.
- depressurization/discharge step 1A-3 is effected in order to reduce the pressure in column 1A from P 1 of 1.2 ata to P 2 of 0.9 ata during discharging of low-enriched oxygen.
- pressurization and pressurization/adsorption steps in column 1B are completed.
- regeneration, pressurization and pressurization/adsorption steps in column 1A and adsorption step in column 1B will be effected.
- adsorption step 1B-1 air which is pressurized by compressor 2 up to P 1 of 1.2 ata is fed from nozzle 110B through valve 11B into column 1B while the pressure in column 1B is being pressurized from P 2 of 0.9 ata to P 1 of 1.2 ata.
- adsorption step 1B-2 is made during which enriched oxygen is supplied into product tank 4 from piping 70 via valves 100B and 14B and stored therein.
- valve 14A Near halfway progression of regeneration step 1A-5, valve 14A is closed and valve 30A is opened, and part of product oxygen is injected from gas injection nozzle 6A.
- column 1B Upon completion of regeneration step 1A-5 in column 1A, column 1B is still in the course of adsorption step 1B-2, during which valve 12B is closed and (in case valves 15A and 6B have been closed already) valves 15A and 16B are opened.
- oxygen concentration indicator mounted at nozzle 100B indicates approximately 50%, or so, the above-mentioned medium-enriched oxygen is discharged.
- medium-enriched oxygen is introduced into column A via nozzles 100B and 110A.
- valve 20B is opened and valve 11B is closed, air is introduced from gas injection nozzle 6B into column 1B via valve 20B.
- pressurization step 1A-6 in column A is effected, in which the pressure in column 1A is increased from P d of 0.48 ata up to P 3 of 0.7 ata by introducing part of product oxygen in product tank 4 into column 1A after valve 3A is closed and pressure regulator valve 5B and valves 14A and 30A are opened.
- column 1B is in the course of adsorption step 1B-2, during which valve 20B is closed when the above-mentioned low-enriched oxygen is detected at the nozzle 100B.
- valve 11A is opened in column A system.
- air flow via valve 11A and low-enriched oxygen flow from valve 100B at the top of column 1B via valve 16B and 15A join before valve 110A, and are injected from nozzle 110A into column 1A.
- injection pressurization/adsorption step 1A-7 is made, which includes pressurization step, wherein the pressure of column 1A is increased from the level of P 3 of 0.7 ata to that of P 2 of 0.9 ata and adsorption step wherein air introduction is made.
- depressurization/discharge stage 1B-3 is made in order to reduce the pressure in column 1B from P 1 of 1.2 ata to P 2 of 0.9 ata during discharging of low-enriched oxygen. Then, adsorption step in column 1B and regeneration, pressurization and pressurization/adsorption steps in column 1A are completed, and one cycle operation is completed. From the second cycle operation the same operation as that in the first cycle is repeated.
- the number of the above-mentioned injection nozzle is not limited to only one, but it can be plural. In case of one injection nozzle it is preferable to install the injection nozzle in the middle part of column 1, or at a location between the middle and the top of column 1. It is possible to make the pressure differential between the column top and the bottom smaller than that in the case of air supply from the bottom of column 1 by installing the injection nozzle at such locations as above-mentioned. Consequently, better contact of feedstock air with the adsorbent is realized, which results in higher utilization rate of adsorbent, i.e., increase of nitrogen quantity to be adsorbed per unit volume of adsorbent and which leads to improvement in yield of product oxygen. Besides, improvement of nitrogen desorption efficiency can be achieved during the injection step of product oxygen because diffusion rate of oxygen into pores in the adsorbent is accelerated.
- a plurality of gas injection holes 700 are prepared in injection nozzle 6.
- the injection holes 700 make it possible to obtain uniform gas flow 600a and 600b, respectively, toward the nozzle at the bottom of column 1 and in radial direction.
- the efficiency of contact of gas with the adsorbent can be improved during the adsorption or injection step, which ensures improvement in adsorbent utilization rate and acceleration of nitrogen adsorption or desorption.
- injection nozzles In case of installing a plurality of the injection nozzles, on the other hand, it is acceptable to install them optionally at any location between the top and bottom of column 1. It is, however, preferable to install them at location levels of one quarter, one half and three quarters of the total height of column 1 from the level of nozzle 110. In addition, even in case a plurality of injection nozzles 6 are provided, the arrangement of injection holes 700 is the same as that in case of single injection nozzle 6, as shown in FIG. 1b.
- sensors 900 for detecting the concentration of nitrogen are provided in the vicinity of injection nozzles 6A1, 6A and 6A2.
- progressive performance (concentration profile or gradient) of the nitrogen adsorption zone is monitored.
- valve 60A1 is opened, and then feedstock air is fed into column 1A under the control of controller 1000.
- injection nozzle 6A is in use, and valve 60A2 is opened the other two injection nozzles 6A1 and 6A2 are out of use.
- injection nozzle 6A2 is in use and only valve 60A3 is opened.
- sensors 900 for detecting nitrogen concentration are provided in the vicinity of injection nozzles 6B1, 6B and 6B2, by which progressive performance of the nitrogen adsorption zone is monitored.
- valve 60B3 is opened under the control of controller 1000 and product oxygen is fed into column 1B.
- valve 60B2 is opened and the other two injection nozzles 6B1 and 6B2 are put out of use.
- injection nozzle 6B1 is in use and only valve 60B1 is opened.
- Operational times were 10 seconds for each of steps 1A1 and 1B-1, 40 seconds for each of steps 1A-2 and 1B-2, 10 seconds for each of steps 1A-3 and 1B-3, 30 seconds for each of steps 1A-4 and 1B-4, 10 seconds for each of steps 1A-5 and 1B-5, 10 seconds for each of steps 1A-6 and 1B-6, 10 seconds for each of steps 1A-7 and 1B-7, 10 seconds for each of feed stock air supply from gas injection nozzles 6A and 6B, and 5 seconds for each of product oxygen supply to column 1A and 1B.
- the output quantity (Q) of product oxygen was about 19.6 Nm 3 /hr at air supply flow rate of 200 Nm 3 /hr, and recovery rate ( ⁇ ) of product oxygen was 42%.
- the latter was more effective than the former in improving the recovery rate ( ⁇ )of product oxygen by 3%.
- Example 1 which offers features of the present invention
- Example 2 will become apparent from FIGS. 4 and 5, which show the case where feedstock air and product oxygen are supplied through nozzle 6A or 6B.
- the pressure in the top of the column becomes P 2 as indicated at point C owing to pressure drop ( ⁇ P) between the top and the bottom of the column, and the quantity of nitrogen adsorbed in the adsorbent in the top zone becomes q 2 . Consequently, the adsorption quantity of nitrogen in the top zone (q 2 ) will become less by ⁇ q than that in the bottom (q 1 ), which shows the adsorbent in the top zone can still afford to adsorb more nitrogen, which is corresponding to near ⁇ q, i.e., the adsorbent in the top zone is not made good use of.
- the pressure in the column top becomes P' 1 , which is obtained by deducting the pressure drop ( ⁇ P') between gas injection nozzle 6A or 6B and the column top from the air supply pressure, and quantity of nitrogen adsorbed becomes q' 1 .
- the nitrogen quantity in the adsorbent in the column top takes a favorable turn to q' 1 , which is larger than q 2 in the conventional cases, and the mean adsorption quantity of nitrogen between the column top and the gas injection nozzle 6A or 6B, where the adsorbent can still afford to adsorb more nitrogen, is increased up to approximately (q' 1 +q 1 )/2, which results in improved utilization rate for an adsorbent, so that the quantity of air to be processed can be increased and the recovery rate of product oxygen can be enhanced.
- FIG. 5 shows state of nitrogen adsorbed in terms of adsorbed nitrogen quantity during regeneration step, where the column is depressurized to pressure P d of 0.48 ata by means of vacuum pump 3.
- P d pressure of 0.48 ata by means of vacuum pump 3.
- the absolute pressure in the top is P 3 which is higher than P d of 0.48 ata, as indicated at point d, and the quantity of nitrogen in the adsorbent becomes q 3 .
- the pressure in the bottom is P 4 of 0.48 ata, as indicated at point e, and the quantity of nitrogen remaining in the adsorbent becomes q 4 , which means that desorption is easier at the bottom than at the top.
- Such difficulties can be overcome by introducing product oxygen simultaneously from, for example, gas injection nozzle 6A or 6B provided at the middle portion of the column and from the top, or by introducing product oxygen from the top of the column to desorb the nitrogen remaining in the adsorbent in the vicinity of the column, and then injecting product oxygen, which contains less nitrogen effective for desorption from gas injection nozzle 6A or 6B to desorb nitrogen remaining in the adsorbent in the top of the column.
- the above-mentioned methods make it possible to desorb simultaneously nitrogen remaining in the adsorbent in the top and the bottom of the column by a predetermined quantity, so that the promotion of the desorption of nitrogen remaining in the adsorbent in the top of the column can be achieved. By so doing, the quantity of air to be fed and processed at subsequent regeneration step can be increased, thereby increasing the output quantity of product oxygen.
- each of columns 1A and 1B was provided with three nozzles, as shown in FIGS. 8 and 9. Namely, columns 1A and 1B were provided with gas injection nozzles 6A1, 6A and 6A2, and 6B1, 6B and 6B2, respectively, at levels of one quarter, one half and three quarters of total height of Column 1 from nozzle 110. Further, columns 1A and 1B were also provided with switching-over valves 40A, 50A, 60A1, 60A2 and 60A3, and 40B, 50B, 60B1, 60B2 and 60B3, respectively, as shown in FIGS. 8 and 9.
- feedstock air was fed from nozzle 110A by keeping pressure regulator valve 5A and valve 11A open and keeping valves 20A, 40A, 50A, 30A, 60A1, 60A2 and 60A3 shut. Thereafter, feedstock air was fed firstly from gas injection nozzle 6A1 after closing valve 11A and opening valves 20A and 60A1, secondly from gas injection nozzle 6A after closing valve 60A1 and opening valves 40A and 60A2, and finally from gas injection nozzle 6A2 after closing valve 60A2 and opening valves 50A and 60A3.
- Feedstock air supply time was set such that 40 seconds of adsorption time in Example 1 included 15 seconds from nozzle 110A, 10 seconds each from gas injection nozzles 6A1 and 6A, respectively, and 5 seconds from gas injection nozzle 6A2. Whilst, an example in ease column 1B is in the product oxygen injection step will be described with reference to FIG. 9. First of all, pressure regulator valve 5B and valve 14B were opened and valves 30B, 50B, 40B, 20B, 60B3, 60B2 and 60B1 were closed, and product oxygen stored in product tank 4 was injected from nozzle 100B.
- product oxygen was fed firstly from gas injection nozzle 6B2 after closing valve 14B and opening valves 20B and 60B3, secondly from gas injection nozzle 6B after closing 60B3 and opening valves 50B and 60B2, and finally from gas injection nozzle 6B1 after closing valve 60B2 and opening valves 40B and 60B1.
- Product oxygen injection time was set such that 10 seconds of product oxygen injection time in Example 1 included 3 seconds from nozzle 100B, 3 seconds from gas injection nozzle 6B2, and 2 seconds each from gas injection nozzle 6B and 6B1, respectively.
- a system is arranged so as to enrich oxygen from air by means of the gas mixture separating apparatus according to the present invention, supply the enriched oxygen into a coal gasification furnace of a coal gasification complex power generating plant to thereby gasify coal, supply the gas into a gas turbine which drives a generator, recover the heat of exhaust gases from the gas turbine by a boiler to thereby generate steam, and supply the steam thus generated into a steam turbine which drives another generator, then the supply cost of oxygen is reduced so that the unit cost of electric power can be reduced correspondingly.
- the adsorption and desorption efficiencies can be increased by providing means for injection of gas into the adsorbent in the adsorption columns, the adsorbent utilization efficiency can be enhanced so that effect of reducing the dimensions of the adsorption columns and lowering the construction cost of the facilities can be achieved.
Abstract
Description
Q=14.9 Nm.sup.3 /hr
Q=22 Nm.sup.3 /hr
η=((22×0.9/200×0.21))×100=47.1%
Claims (22)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP1-290526 | 1989-11-08 | ||
JP01290526A JP3076912B2 (en) | 1989-11-08 | 1989-11-08 | Method and apparatus for separating mixed gas |
Publications (1)
Publication Number | Publication Date |
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US5104426A true US5104426A (en) | 1992-04-14 |
Family
ID=17757168
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US07/608,350 Expired - Fee Related US5104426A (en) | 1989-11-08 | 1990-11-02 | Method of and apparatus for separating gas mixture |
Country Status (3)
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US (1) | US5104426A (en) |
JP (1) | JP3076912B2 (en) |
KR (1) | KR0149667B1 (en) |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5256172A (en) * | 1992-04-17 | 1993-10-26 | Keefer Bowie | Thermally coupled pressure swing adsorption |
US5529607A (en) * | 1995-03-15 | 1996-06-25 | The Boc Group, Inc. | PSA process with dynamic purge control |
EP0856348A2 (en) * | 1997-02-03 | 1998-08-05 | Bayer Ag | Process for separating gas mixtures by pressure swing adsorption in a two-bed adsorption system |
EP0884087A2 (en) * | 1997-05-14 | 1998-12-16 | Air Products And Chemicals, Inc. | Pressure swing adsorption process with a single adsorbent bed |
US5917135A (en) * | 1996-06-14 | 1999-06-29 | Invacare Corporation | Gas concentration sensor and control for oxygen concentrator utilizing gas concentration sensor |
US6478850B2 (en) * | 2000-08-02 | 2002-11-12 | Wearair Oxygen Inc. | Miniaturized wearable oxygen concentrator |
US6547851B2 (en) * | 2000-08-02 | 2003-04-15 | Wearair Oxygen Inc. | Miniaturized wearable oxygen concentrator |
US20040055465A1 (en) * | 2000-12-29 | 2004-03-25 | Alain Guillard | Method for treating a gas by adsorption and corresponding installation |
US20050199122A1 (en) * | 2002-04-15 | 2005-09-15 | Nippon Sanso Corporation | Gas separating method |
WO2006086432A3 (en) * | 2005-02-09 | 2007-11-22 | Vbox Inc | Method and apparatus for controlling the purity of oxygen produced by an oxygen concentrator |
US20090107331A1 (en) * | 2005-11-14 | 2009-04-30 | Tatsushi Urakami | Method and Apparatus for Pressure Swing Adsorption |
CN1649646B (en) * | 2002-04-29 | 2010-12-08 | 赛科技术有限公司 | Portable oxygen concentration system |
US20160332105A1 (en) * | 2015-05-15 | 2016-11-17 | Robert F. Tammera | Apparatus and System for Swing Adsorption Processes Related Thereto |
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CN1649646B (en) * | 2002-04-29 | 2010-12-08 | 赛科技术有限公司 | Portable oxygen concentration system |
WO2006086432A3 (en) * | 2005-02-09 | 2007-11-22 | Vbox Inc | Method and apparatus for controlling the purity of oxygen produced by an oxygen concentrator |
US20090107331A1 (en) * | 2005-11-14 | 2009-04-30 | Tatsushi Urakami | Method and Apparatus for Pressure Swing Adsorption |
US7824472B2 (en) * | 2005-11-14 | 2010-11-02 | Taiyo Nippon Sanso Corporation | Method and apparatus for pressure swing adsorption |
US20160332105A1 (en) * | 2015-05-15 | 2016-11-17 | Robert F. Tammera | Apparatus and System for Swing Adsorption Processes Related Thereto |
US9861929B2 (en) * | 2015-05-15 | 2018-01-09 | Exxonmobil Upstream Research Company | Apparatus and system for swing adsorption processes related thereto |
Also Published As
Publication number | Publication date |
---|---|
KR910009324A (en) | 1991-06-28 |
KR0149667B1 (en) | 1998-10-15 |
JPH03151014A (en) | 1991-06-27 |
JP3076912B2 (en) | 2000-08-14 |
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